attribute
const
uniform
varying
layout
centroid
flat
smooth
noperspective
break
continue
do
for
while
switch
case
default 
if
else
in
out
inout
float
int
void
bool
true
false
invariant
discard
return
mat2
mat3
mat4
mat2x2
mat2x3
mat2x4
mat3x2
mat3x3
mat3x4
mat4x2
mat4x3
mat4x4
vec2
vec3
vec4
ivec2
ivec3
ivec4
bvec2
bvec3
bvec4
uint
uvec2
uvec3
uvec4
lowp
mediump
highp
precision
sampler1D
sampler2D
sampler3D
samplerCube   
sampler1DShadow
sampler2DShadow
samplerCubeShadow
sampler1DArray
sampler2DArray
sampler1DArrayShadow
sampler2DArrayShadow
isampler1D
isampler2D
isampler3D
isamplerCube
isampler1DArray
isampler2DArray
usampler1D
usampler2D
usampler3D
usamplerCube
usampler1DArray
usampler2DArray
sampler2DRect
sampler2DRectShadow
isampler2DRect
usampler2DRect
samplerBuffer
isamplerBuffer
usamplerBuffer
sampler2DMS
isampler2DMS
usampler2DMS
sampler2DMSArray
isampler2DMSArray
usampler2DMSArray
struct